A weird IP in this HA K8S deployment doc 10.10.40.10 ?

[akatukiyou]

I am following this doc to setup a HA K8S cluster with 3 master and 5 worker nodes.

Question 1
In the section of [7- Create an etcd systemd unit file] under [Installing and configuring Etcd] , suddenly there was an IP address which never mentioned anywhere showed up -- 10.10.40.10 The setup in this doc has no subnet of 10.10.40.x defined.

--listen-peer-urls https://10.10.40.10:2380 \

wondering if it was a typo or this IP means something?. This IP here does not make any sense in this config file. There is another 10.10.40.x IP address in this doc which was also suddenly just showed up from no where.

listen-peer-urls should be set to other 2 master machines or just itself?

Question 2
Then, at the beginning of the doc, it was mentioned that an IP range for the pods will be 10.30.0.0/16 --- /16
But in the later section Initializing the master nodes it set to networking: podSubnet: 10.30.0.0/24 ??

Thanks